It is not enough to do the currently recommended sport to really reduce the risk of heart attack: according to research (which is causing discussion), led by Macao Polytechnic University (China)adults would need to perform between 560 and 610 minutes per week of moderate or high intensity physical activity to achieve this result (which, however, remains statistical).
This value is 3 to 4 times higher than what is currently recommended, given that the indications currently include at least 150 minutes per week of moderate or high intensity physical exercise for adults, such as brisk walking, running or cycling.
The study also suggests that less trained people need slightly more exercise than highly trained people to achieve the same cardiovascular benefits, and researchers say that current standardized exercise recommendations may need to be modified and replaced by goals tailored to individual fitness levels.
Cardiorespiratory fitness, in fact, varies considerably and is a strong predictor of cardiovascular health: if low, in particular, it is strongly associated with an increased risk of heart attack, stroke and premature death.
The study included data from 17,088 people who participated in a study between 2013 and 2015, whose average age was 57, with 56% female and 96% Caucasian. Participants wore a device on their wrist for seven consecutive days to record their typical exercise levels and completed a cycle ergometer test to measure their VO2 max estimate, i.e. the maximum volume of oxygen consumed per minute (expressed in ml/kg/min), which, in fact, measures the efficiency with which the heart, lungs and muscles supply and use oxygen.
Data such as smoking, alcohol consumption, perceived health, nutrition, body mass index, resting heart rate and blood pressure were also considered in the analysis.
During an average follow-up period of 7.8 years, 1233 cardiovascular events occurred, including 874 cases of atrial fibrillation, 156 myocardial infarctions, 111 cases of heart failure and 92 strokes.
The research found that adults who met guidelines of 150 minutes of exercise per week experienced a modest reduction in cardiovascular risk of 8-9%, which was consistent across all fitness levels.
According to the authors, between 560 and 610 minutes of moderate-to-vigorous intensity physical exercise per week would be needed to achieve substantial protection, defined as a risk reduction greater than 30%. However, only 12% of study participants achieved this level of physical activity.
The analysis also found that individuals with the lowest fitness levels needed approximately 30-50 minutes more exercise per week than those with the highest fitness levels to achieve equivalent benefits.
This result highlights the greater difficulty encountered by untrained populations
the researchers write
Since this is an observational study, however, it is not possible to draw definitive conclusions regarding a cause-effect relationship. The researchers, for example, acknowledge that the study group may have been healthier and fitter than the general population. Among other things, the estimation of cardiorespiratory fitness, which occurred without measuring the time spent in sedentary activities or during lower intensity exercises.
However, the researchers say their findings confirm that current guidelines provide a solid universal minimum for cardiovascular protection. But they add that specific guidance should be provided to help motivated patients to do more to protect their heart health.
Future guidelines may need to distinguish between the minimum volume of moderate-to-vigorous intensity exercise required for a baseline safety margin and the substantially higher volumes needed for optimal cardiovascular risk reduction
they conclude.
The work was published on British Journal of Sports Medicine.
Sources: BMJ Group / British Journal of Sports Medicine
